This year we read philosophical works by Rene Descartes and David Hume. In their writings, both Descartes and Hume strive to answer the question, “How do we know what we know?” Is knowledge essentially gained through reason or through experience? While these two positions at first seem antithetical, they are actually tightly linked in that the very act of reasoning is an experience and that the processing of experiences requires reasoning. If a being can engage in thinking, then it not only exists, but is having an experience; and if a being can question and draw inferences from its experiences, then it is reasoning.
From the seventeenth to the eighteenth century, both rationality and empiricism became hallmarks of what would later be called the period of Enlightenment. Philosophy of existence and causality (as opposed to philosophy of morality) was as much a science as physics; understanding in one discipline would often be used to explain the other. Enlightenment thinkers championed skepticism, abstract reasoning, and testability.
In his Meditations on the First Philosophy, Descartes strives to arrive at one absolute truth which can act as the foundation for all the sciences. In the first two meditations, through a carefully and brilliantly laid out argument, Descartes arrives at what he believes to be the one irrefutable truth: he thinks. He can think. Because he can think, he must exist. Because he can conceive of himself, his mind must exist.
He proceeds in the next meditation to extend this reasoning to God. That he can conceive of God proves that God must exist. For how could a finite being conceive of something outside itself? This concept of God must have a cause and that cause must be God Himself.
Descartes spends the rest of his time building upon this method of reasoning, extending it to the material world. He believes that the corporeal world can most accurately be apprehended through careful reasoning. This, he believed, would lay a solid foundation for understanding all the sciences. It must be understood that this is where Descartes is headed all along. He seeks to buttress the discoveries of science with reasoning, not demolish them. But perhaps his defense of the existence of God obscures his intent.
It certainly seems that Hume took issue with Descartes’ defense of the existence of God. One wonders if Hume would have denounced Descartes so viciously in ECHU if Descartes had not attempted to prove the existence of God. Hume categorically opposes Descartes’ reasoning here, but elsewhere in Enquiry, he warns against dispelling abstract reasoning altogether.
But the importance of Hume’s writing lies in his careful exegesis of how we perceive both experiences and ideas. He argues that experiences precede ideas. A being can have no conception of what he has not experienced. All thoughts, ideas, memories, even dreams, are based in experience. Causality can only be inferred, and meaning can only be conferred.
This method of understanding the world, that is conferring meaning from the observable, would set the stage for the exaltation of empiricism over reasoning. While Hume clearly did not propose eradicating reason, the idea that facts and experience exist first and that man must connect the dots between the facts we observe has taken on gargantuan meaning in our own century. It has become difficult to argue that anything has cause, meaning or even existence, if it cannot be observed and tested.
These two works are seminal because they raise the issues of questioning accepted institutions; accepted methods of understanding ourselves, our world and even God; and because they each introduce a systematic method of enquiry. The influence of this kind of systematic skepticism reaches through three centuries to our own time and has become a fundamental component of 21st-century learning.